Polyamide-thickened grease



Uiteti. htates Patent O "ice 2,830,955

Patented Apr. 15, 1958 diamine reaction product is-then further treated with a sufiicient amount of a primary or secondary amine (or 2,830,955 mixtures thereof) to completely react with the residual n MID as I carboxyl groups, forming the thickening agent of this in- PQL [A i E TMICKENED GREASE vention. For sake of brevity, this'thickening agent will Eoseph A. Dixon, Beiiwood, 'Pa., assignor'to California be termed Polyamide, which polyamide is represented Research Corporation,'San Francisco, Calif., a corpob F l A h i b l rahhh of Delaware The reactions involved in the preparation of this thi'ck- No Drawing. Application'November-ZS, 1955 F emng ,agent are exemphfied as follows:

Serial No. 548,750 Equatwn 1 a o 0 6 Claims. (Cl. 252-515) H H YIX 1 X(H2N-RNH2) Y(HOCR|COH) t O o 0 This patent application is directed to new grease thick- HO g g L ening agents for the formation of high temperature grease compositions. Specifically, this patent application is di- Equation 2 0 o 0 0 R: I! g g g E! II HOCRi (NH-R-NH- Ri -NHRNH RiC),OH /NH R: O 0 (ii? 0 (I) 0 /R2 Ntih-lh-i")--(NHR NH-O-RiJiJ-NHR- NHJJ-Ri .-N Ra Ra rected to high temperature grease compositions prepared Formula A with certain particular polyamides.

This application is a continuation-in-part of patent ap- Wherelh R, R1 h 2 allphahc ffldlcals, 3 15 lf plication Serial No. 305,290, filed August 19, 1952 (and gen or a p t a i l, a d Y{X is the molar ratio of now abandoned) dibasic acid to diamine, which ratio has a value from 1.6

It is becomingmoreand more apparent that, for the to about 4 hi Preferred) most part, greases must be able to lubricate effectively The Values of Z 111 h a o e equations are not fixed at high temperatures; that is, temperaturegi the range r values for any one reactlon. T 0 those shilled n the art, f 350 to 500 F f ablyw b 400 Numer. it-is understandable that, although z is an integer, a ous grease specifications of government agencies and incert'fllh degree Varlahon 1S eXPenenPed Wlthlll F -Y 9 dustries nowspecify grease compositions having mini- Parhcular a 111 fofmatloh of thlckenmg mum dropping points of 400 F. This need for high temagents of t s Invention, the average value for 2 y perature greases is the result of increased driving power, 4r y y from about t0 which increases thespeeds of gears, bearings, and other J The R and R1 E 'Q P are PUB/methylene groups moving parts; increased pressure caused by the develop- (CHM): Whfeln 15 a number from the R g llPS from, ment of smaller gears to withstand greater loadsthan 2 to 10 (4 to 6 belhg heretofore possible with larger gears, etc 2 and s (Where 8 not hydrogen) a ahphahc Greases prepared according to the present .invention radicals containing from 2 to 22 carbon atoms (4 to- 16 will maintain grease consistencies at extremelyhigh tem- Carbon atoms helhg Preferred)- peratures; that is, such greases will remain unctuous and is Preferred that R a hexamethylehe h hh h not become hard or brittle at temperatures in the range R1 15 a tehhmethylehe radlcal; that 2 15 an ahphahc of 350 F. to 500- F. cal containing from 4 to 16 carbon atoms; and that R 18 Inthe automotive industry, for example, there is the hydrogehconstant desire to manufacture smaller internal combus- Examples of and 1 groups lllkclllde imethylene, tion engines without sacrificing power output. In fact, tnmethylene, h if ne, oetamethylene, octadecylmany of thesesmallenengines. aredesigned to deliver methylene; radlcah dhnved from Petroleum hydrocargreater'power than their larger counterparts. The same hohs" Such as Whlte Olefin Polymers, smaller engines have considerably less bearing surfaces Example? of the 2 and R3 Tadlcals (when s 15 not than the larger predecessors, which means that the bearhydrogen) Include the followlhg: ethyl, propyl, P P YL ings bear greater loads than before butyl, hexyl, octyl, octenyl, nonyl, decyl, dodecyl, tetra- Similarly the continuing trend to manufacture decyl, hexadecyl, octadecyl, eicosyl; radicals derived from mobiles with lower centers of gravity has. made it necespe'iroleum eltlydrocarbons such as Whlte WaX"1ehn sary to use smaller driving gears, particularly in such gear p0 ymers assemblies as the diiferentials and transmissions; The When h mm) of Y/ Equahoh 1 heremabove has smaller gears thus used have considerably greater pres- Value of the reshhmg Polymer 13 Of'the nylon type sures exerted upon them per unit area than gears of polymehc compouhgs' AS set forth in h for older type gear assemblies; The. higher loads on bear- Synthehc Polymers, y Rowland H111 P i by ings and gears demand beter thickening agents in grease Elsevler Phhhshmg Company): 1953, P 1133 The compositions. word nylon is not a trade name, but a word coined as According to the present invention, lubricating oils are a gehehc term for a syhthehc fiber-formlyle P thickened to the consistency of greases by incorporating Further on Page of the same text 1t 18 Stated that certain polyamides therein. These polyamides'are prethe molecular Welghts of synthetic fiber-forming P W" pared by first reacting a dicarboxylic acid with a diamine, amides usually eXceed wherein the molar ratio of dicarboxylic'acid to amine has AS pp to the 3/ p Polymerie compounds,

at value from, 1.6 to about 4. The dicarboxylic acidthe molecular weights of the dibasic acid-diamine poly- 2 meric compounds used herein as grease thickening agents are less than 1000.

Lubricating oils which are suitable base oils for the grease composition of this invention include a wide variety of lubricating oils, such as naphthenic base, paraffin base, and mixed base, other hydrocarbon lubricants, e. g., lubricating oils derived from coal products, and synthetic oils, e. g., alkylene polymers (such as polymers of propylene, butylene, etc., and mixtures thereof), alkylene oxide type polymers, dicarboxylic acid esters, liquid esters of acids of phosphorus, alkyl benzene polymers, polymers of silicon, etc. Synthetic oils of the alkylene oxide type polymers which may be used include those exemplified by the alkylene oxide polymers (e. g., propylene oxide polymers) and derivatives, including alkylene oxide polymers prepared by polymerizing the alkylene oxides, e. propylene oxide, in the presence of water or alcohols, e. g., ethyl alcohol; esters of ethylene oxide type polymers, e. g., acetylated propylene oxide polymers prepared by acetylating propylene oxide polymers containing hydroxyl groups; polyethers prepared from the alkylene glycols, e. g., ethylene glycol, etc.

The polymeric products prepared from the various alkylene oxides and alkylene glycols may be polyoxyalkylene diols or polyalkylene glycol derivatives; that is, the terminal hydroxy group can remain as such, or one or both of the terminal hydroxy groups can he removed during the polymerization reaction by esterification or etherification.

Synthetic oils of the dicarboxylic acid ester type include those which are prepared by esterifying such dicarboxylic acids as adipic acid, azaleic acid, suberic acid, sebacic acid, alkenyl succinic acid, fumaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, 2- ethylhexyl alcohol, dodecyl alcohol, etc. Examples of dicarboxylic acid ester synethetic oils include dibutyl adipate, dihexyl adipate, and di-Z-ethylhexyl sebacate.

Synthetic oils of the alkylbenzene type include those which are prepared by alkylating benzene (e. g., dodecyl benzene, tetradecyl benzene, etc.).

Synthetic oils of the type of liquid esters of acids of phosphorus include the esters of phosphoric acid, e. g., tricresyl phosphate; the esters of phosphonic acid, e. g., the diethyl ester of decanephosphonic acid, etc.

Synthetic oils of the type of polymers of silicon include the liquid esters of silicon and the polysiloxanes. The liquid esters of silicon and the polysiloxanes include those exemplified by tetraethyl silicate, tetraisopropyl silicate, tetra(methyl-2-butyl) silicate, silicate, tetra( l-methoxy-Z-propyl) silicate, hexyl(4- methyl-2-pentoxy) disiloxane, poly(methylsiloxane) poly- (methylphenylsiloxane), etc.

The above base oils may be used individually as such or in various combinations, wherever miscible or wherever made so by the use of mutual solvents.

The grease-thickening agents of this invention can be used in amounts sufficient to thicken the oils to the consistency of a grease; that is, in amounts of 6% to 50%, by weight; however, 10% to 30% by weight are preferred.

As so forth in Examples 1 and 2 hereinbelow, the nylon type polyamides do not thicken lubricating oils to consistency of greases.

Example 1.Attempted preparation of grease compositions from nylon 66 A mixture of grams of nylon 66 (i. e., a nylon prepared by hexamethylene diamine and adipic acid) and 75 grams of a California naphthenic base oil having a viscosity of 450 SSU at 100 F. was heated to a temperature of 475 F. with violent agitation. The nylon melted in the temperature range of 400-450 F. However, the nylon was not miscible with the oil, even at the top temperature. When the mixture was cooled to room temperature. the nylon separated out as a solid cake.

tetra(4-methyl-2-penta) v Example 2.Attempzed preparation of grease composifirms from nylon 610 A mixture of 25 grams of nylon 610 (that is, a nylon prepared from hexamethylene diamine and sebacic acid) and 75 grams of a California naphthenic base oil having a viscosity of 450 SSU at 100 F. was heated to a temperature of 475 F. The nylon melted in the temperature range of 400450 F. However, the nylon was not miscible with the oil, even at the top temperature. When the mixture was cooled to room temperature, the nylon separated out as a solid cake.

The following examples illustrate the preparation of the polyamides of this invention and the grease compositions prepared therefrom:

Example 3 A mixture of 77.5 grams (0.5 mol) hexamethylene diamine (75% solution in water) and 146 grams (1 mol) of adipic acid was slowly heated with stirring. Water of reaction began to come from the reaction mixture at 240 F. 20 minutes later, the temperature had reached 390 F., at which temperature the water of reaction ceased. To this reaction mixture 244 grams (0.9 mol) of Armeen HTD (defined hereinbelow) was added dropwise at temperatures ranging from 390430 F. over a period of 30 minutes. The reaction mixture was heated for an additional 5 minutes at 430 F. The cooled reaction product Was a tan solid.

30 grams of the above reaction mixture.(i. e., the tan solid) and 170 grams of a California solvent-refined naphthenie base oil having a viscosity of 450 SSU at 100 F. were heated, with stirring, to 470 F. This mixture was cooled to room temperature and milled through a ZOO-mesh screen. The resulting grease had a dropping point of 467 F. and an ASTM worker penetration of 230 strokes).

Example 4 A mixture of 77.5 grams (0.5 mol) of a aqueous solution of hexamethylene diamine and 219 grams (1.5 mols) of adipic acid was heated, with stirring, to 420 F. The reaction mixture was kept at this temperature until the water of reaction had ceased. To this reaction mixture was added 622 grams (2 mols) of Armeen HT (defined hereinbelow). The temperature was maintained at 440450 F. until all of the water of reaction had ceased. On cooling, the reaction product was a hard, brittle, cream-colored solid.

A mixture of 30 grams of the above reaction product and 170 grams of a California solvent-refined base oil having a viscosity of 450.SSU at F. was heated, with stirring, to 470 F. The reaction mixture was cooled to room temperature, then milled through a ZOO-mesh screen. The resulting grease had a dropping point of 452 F. and an ASTM penetration of 250 (60 strokes).

Example 5 A mixture of 101 grams (0.5 mol) of sebacic acid and 27 grams (0.25 mol) of 2,6-diaminopyridine was heated, with stirring, to a final temperature of 440 F. until the water of reaction ceased. To this reaction mixture grams (0.5 mol) of Armeen HTD was added dropwise over a period of 10 minutes. 'The whole reaction mixture was heated to a temperature of 440 F. until the water of reaction had ceased. The cooled reaction product was a brittle, greenish-brown solid.

A mixture of 30 grams of the above reaction product and grams of a California solvent-refined naphthenic base oil having a viscosity of 450 SSU at 100 F. was heated to 520 F. The mixture was cooled to room temperature and milled through a ZOO-mesh screen.

Table I hereinbelow presents further data on grease preparations of this invention. Except for greases of Experiment Nos. 13 and 14, which contain 10%, all of assooss h cken n e Thesabbreviations of Table Icaresdefined. as .follows:' fifHTD. is fArmeen HTD, a product,.of Armour &

6 I -tl k ns.,a en .her in ema a y t s mxi ,tion andrustingaction. ,Greases,prepared therefrom are highly resistant. to oxidation, and rusting.

,In additionto thegreasethickeningagents of this in- Company; Chicago, Illinois,.containing n-hexadecyl- 5-.yention, the grease Composition may includeother agents amine, 70% n-octadecylamine, and 5% n-octadecenylwhich willffurther enhanceresistance to oxidation,.other ..-amine. ZHT is .Armeen .HT,. a composition containextreme pressurecharacteristics, resistance to wear; agents ing 25% n-hexadecylamine,.70% n-octadecylamineand .which serve as color correctors, ,rustinhihitors, thicken- 5% n-octadecenylamine, 85 of the whole of. such amines ing agents, etc. consisting of n-primary amines. 10 Ilclaim:

fCD, is ,fArrneen CDR an amine mixture consisting 1. A grease composition comprising a major. proporof 8% n-oetylamine, 9% n-decylamine, 47%..n-dodecyl- ,tion of. a lubricating oil and, in an amountsufficient to amine,5 18% :n-tetradecylamine, 8 n-hexadecylamine, .;.thicken said lubricating oil to the consistencyof a grease, 5%;n=octadeoylamineand5%.nwoctadecenylamine. av g a h k l ag t obtai ed-by. first forming a :;R in; each thickenenwas hydrogen. 15. polyamide having,terminal.carboxylicacid groupsby retBase1oil-Awas a1Qalifornia solyentrrefined ,naphthenic acting aliphatic ibasi .aCidscOnta Di g from 4 to. 12 ;.b e, oi1 h vi a visoqsity f 450,5SU t. 1 00vF, carbon atoms, and, aliphatic diamines containing from 2 Base oil B was a California heavy whit il, to 22 carbon atoms, wherein the mol ratioof said dibasic TABLE I .Thlckener composition Greasepropert Exp. N0- a i iil l giiig st iiiitiii? Base R group B; group R; group mol point worked oil dia- F.) (60 mine strokes) (CHM (CHM HTD 2 467 230 A (CH2)2 (011:)4 HTD 2 500+ 226 A CH3 (CHZM HTD 2 416 305 A fine-CH2 E853: 2E3: his is it? 335 t (011m (CH2); HTD 2.6 446 222 A (CHrge (011204 HT 3 452 250 A (CH2 5 (CH2)4 CD 2 365 A 2)o (CH2); HT 4 375 A (CH2 (C1194 2 436 271 A 11 (OH2)6+ (CH2); HT 2 410 361 A %p-phenyl 12 iilflz) (01194 HT 1.8 454 284 B 13 CH3 (0112)., HT 2 428 824 A Hz CH2 and (CH2):

2 E8532 E8532 di it 228 233 1% The data presented hereinbelow in Table I! show (1) acids to said diamines has a value from 1.5 to 4, followed the etiectiveness of the thickening agents of this invention by reacting the resulting polyamide with n-primary amines in resisting oxidation, (2) the extreme pressure charactercontaining from 2 to 22 carbon atoms in an amount sufiiistics, and (3) resistance to wear. The Norma Hoffman cient to form an amide with the residual acid groups of ASTM D-942 oxidation stability test measures the loss said polyamide, the resulting grease thickening agent havin oxygen pressure over a period of 100 hours and S00 ing a molecular weightless than 1000. hours. The Almen test, which measures the loss in 2. A grease composition comprising a major proporwear (steel over bronze) at a pressure of 8 p. s. i. during tion of a lubricating oil and, in an amount sufiicient to a period of 5 minutes, is described in Lubricants and thicken said lubricating oil to the consistency of a grease, Lubrication, by Clower, published by McGraw-Hill Book a grease thickening agent obtained by first forming a Company in 1939, pages 145 to 148. The Falex test, polyamide having terminal carboxyl groups by reacting which measures wear loss at several pressures (steel on aliphatic dibasic acids containing from 6 to 8 carb steel), is described in Journal of the Institute of Peatoms and aliphatic diamines containing from 4 to 6 cartroleum, vol. 32, April 1946. bon atoms, wherein the mol ratio of said dibasic acids to Greases Nos. 13 and 14 are, respectively, those of Ex- Sa dia es has a value from 1.5 to 4, followed by periment Nos. 13 and 14 of above Table I. reacting the resulting polyamide with n-primary aliphatic e amines containing from 4 to 16 carbon atoms in an TABLE II amount sufficient to form an amide with the residual acid groups of said polyamide, the resulting grease thickening Falex Wear test Norma Hoffman agent having a molecular weight less than 1000. Grease No. 155) 533? test 3. A grease composition comprising a major propor- (mg. tion of a lubricating oil and, in an amount suflicient to 125 5001,35 loss) 100 hm 500 thicken said lubricating oil to the consistency of a grease,

a grease thickening agent obtained by forming a poly- 13 2, 6 L2 M 5 17 amide having terminal carboxyl groups by reacting adipic 14 8 acid and hexamethylene diamine, wherein the mol ratio of adipic acid to said diamine has a value from 1.5 to 4,

followed by reacting the resulting adipic acid-hexamethylene diamine polyamide with n-primary octadecylarnine in an amount sufiicient to form an amide with the residual carboxylic groups of said polyamide, the resulting grease thickening agent having a molecular weight less than 1000.

4. A grease composition comprising a major proportion of a lubricating oil and, in an amount sufiicient to thicken said lubricating oil to the consistency of a grease, a grease thickening agent obtained by forming a polyamide having terminal carboxylic groups by reacting adipic acid and hexamethylene diamine, wherein the mol ratio of adipic acid to said diamine has a value from 2 to 3, followed by reacting the resulting adipic acidhexamethylene diamine polyamide with n-primary octadecylamine in an amount suificient to form an amide with the residual carboxylic groups of said polyamide, the resulting grease thickening agent having a molecular weight less than 1000.

5. A grease composition comprising a major proportion of a lubricating oil and from 6% to 50% by weight of a grease thickening agent obtained by forming a polyamide having terminal carboxylic groups by reacting adipic acid and hexamethylene diamine, wherein the mol ratio of adipic acid to said diamine has a value of 1.5 to 4,

5 followed by reacting the resulting adipic acid-hexamethylene diamine polyamide with n-primary octadecylamine in an amount sufiicient to form an amide with the residual carboxyl groups of said polyamide, the resulting grease thickening agent having a molecular weight less than 1000.

6. A grease composition comprising a major proportion of a lubricating oil and from 10% to 30% by weight of a grease thickening agent obtained by forming a polyamide having terminal carboxylic groups by reacting adipic acid and hexamethylene diamine, wherein the mol ratio of adipic acid to said diamine has a value of 1.5 to 4, followed by reacting the resulting adipic acid-hexamethylene diamine polyamide with n-primary octadecylamine in an amount sufiicient to form an amide with the residual carboxylic groups of said polyamide, the resulting grease thickening agent having a molecular weight less than 1000.

Bryant et al Apr. 29, 1952 Bryant et a1. July 22, 1952 

1. A GREASE COMPOSITION COMPRISING A MAJOR PROPORTION OF A LUBRICATING OIL AND, IN AN AMOUNT SUFFICIENT TO THICKEN SAID LUBRICATING OIL TO THE CONSISTENCY OF A GREASE, A GREASE THICKENING AGENT OBTAINED BY FIRST FORMING A POLYAMIDE HAVING TERMINAL CARBOXYLIC ACID GROUPS BY REACTING ALIPHATIC DIBASIC ACIDS CONTAINING FROM 4 TO 12 CARBON ATOMS AND ALIPHATIC DIAMINES CONTAINING FROM 2 TO 22 CARBON ATOMS, WHEREIN THE MOL RATIO OF SAID DIBASIC ACIDS TO SAID DIAMINES HAS A VALUE FROM 1.5 TO
 4. FOLLOWED BY REACTING THE RESULTING POLYAMIDES WITH N-PRIMARY AMINES CONTAINING FROM 2 TO 22 CARBON ATOMS IN AN AMOUNT SUFFICIENT TO FORM AN AMIDE WITH THE RESIDUAL ACID GROUPS OF SAID POLYAMIDE, THE RESULTING GREASE THICKENING AGENT HAVING ING A MOLECULAR WEIGHT LESS THAN
 1000. 